attoSHPM+

low temperature scanning Hall probe microscope

INCLUDED FEATURES

125 μm scan range @ 4 K

closed loop scanning @ 1nm resolution

The attoSHPM+ is a compact scanning Hall probe microscope, designed particularly for operation at low temperature and high magnetic fields. At the heart of the attoSHPM+, a molecular beam epitaxy (MBE) grown GaAs/AlGaAs​ Hall sensor measures magnetic fields with unrivalled sensitivity. Local measurements of the magnetization of a sample are obtained by scanning the sample underneath the Hall sensor and simultaneously recording the Hall voltage, directly yielding the local magnetic stray field.

While other local probes may outperform the Hall sensor with respect to its lateral resolution, its ability to non-invasively obtain quantitative values for the local magnetic field makes the Hall sensor a unique tool for the study of superconductors and magnetic materials. The attoSHPM+ features an interferometric encoder for closed loop operation with 1 nm resolution, and an ultra large range scanner with 125 µm scan range at 4 K.

COMPATIBLE COOLING SYSTEMS

Closed Loop Scanning & Ultra-Large Scan Range

...included with any attoSPM+

Using piezo-based scanners usually relies on the assumption that the relation between applied voltage and displacement is linear. In reality, most scanners show large non-linear behaviour and hysteresis, especially for large scan ranges. Creep, i.e. drift in position after approaching a certain location, is a further phenomenon which is common to all piezo scanners. In some experiments, reproducibly locating a small feature on a surface is crucial, and sometimes hysteresis and non-linearity in the acquired image are not acceptable.

This is why the new attoDRY LAB microscopes attoSPM+ are now all equipped with attocube’s unique fiber-based interferometer for closed loop functionality with a resolution of 1 nm. Besides, we managed to further increase the available scan ranges from 50 μm x 50 μm at 300 K and 30 μm x 30 μm at 4 K to a stunning 80 μm x 80 μm at 300 K, and an even larger 125 µm x 125 µm at 4 K.

Since this covers an area larger by more than a factor of 16, locating and recovering your region of interest has never been that easy. Naturally, this large range is also covered by our closed loop encoder.

Closed Loop1

Interferometric Encoder

steady-state resolution (100 ms sample time)

1 nm rms typ.

contouring error (10 μm lines)

12 nm @ 1 μm/s scan speed 80 nm @ 10 μm/s scan speed

time constant (1 μm step response)

11.7 ms

1closed loop functionality currently available in combination with a microscope housing and an ASC500 SPM controller

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Suitable Low Vibration Cryostats

top-loading cryogen free and helium based systems with fast turn-around times

attoLIQUID3000

other cryostats available on request

attoLIQUID5000

Domain Imaging in BaFeO

The 15 μm x 15 μm sized image shows a sample of BaFeO recorded with an attoSHPM, recorded at 4.2 K. The SHPM sensor was kept in a constant height of about 200 nm. The color scale spans 106 mT (dark to bright), while the S/N ratio of this measurement yields an exceptional 50 000:1. Note that SHPM records absolute field strength as opposed to MFM techniques, that record only field gradients.